class Solution1 {
    public boolean isSubtree(TreeNode root, TreeNode subRoot) {
        if(root == null || subRoot == null) {
            return false;
        }
        if(isSameTree(root,subRoot)) {
            return true;
        }

        return isSubtree(root.left,subRoot)||isSubtree(root.right,subRoot);
    }
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if(p != null&&q == null||p == null&&q != null) {
            return false;
        }
        if(p == null && q == null) {
            return true;
        }
        if(p.val != q.val) {
            return false;
        }
        return isSameTree(p.left,q.left) && isSameTree(p.right,q.right);
    }
}
